科学家在澳大利亚发现人类最早祖先的证据

科学家在澳大利亚发现人类最早祖先的证据

Geologists in Australia have found evidence of mankind’s earliest ancestor – a 555 million-year-old worm-like creature smaller than a grain of rice.

澳大利亚的地质学家发现了人类最早祖先的证据——一种5.55亿年前的蠕虫状生物，比一粒米还小。

Scientists on Monday said the prehistoric tiny worm, found in the Australian outback, represents one of the most significant primordial finds ever.

周一，科学家们说，在澳大利亚内陆发现的这种史前微小蠕虫，代表了有史以来最重要的原始发现之一。

“It’s the oldest fossil we get with this type of complexity,” said Mary Droser, a professor at the University of California Riverside and among the scientists who made the discovery. “We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for.”

加州大学河滨分校教授玛丽·德罗泽说：“这是我们发现的最古老的、具有这种复杂性的化石。”。“我们知道我们也有很多小东西，而且我们认为这些可能就是我们正在寻找的早期两侧对称动物。”

Bilaterians are animals with bilateral symmetry, organisms that have symmetrical sides, a head, and openings on both ends connected by a gut.

两侧对称动物，有对称的两边，一个头，两端的开口由肠道连接。

Scientists have long agreed that bilaterians created fossilized burrows found in deposits in Nilpena, South Australia, but had been unable to prove it.

长期以来，科学家们一致认为，在南澳大利亚的尼尔佩纳(Nilpena)的沉积物中发现的化石洞穴是由两侧对称动物创造的，但一直无法证明这一点。

Droser Lab/UCR/SWNS

But new 3-dimensional laser scanning technology finally enabled researchers to identify the new creature, named Ikaria warjootia, as the culprit behind the burrows.

但新的三维激光扫描技术，最终使研究人员能够识别出这个名叫伊卡里亚·沃乔蒂亚(Ikaria warjootia)的新生物，就是这些洞穴背后的罪魁祸首。

The organism is no bigger than seven millimeters long and less than two millimeters wide.

这种生物体长不超过7毫米，宽不到2毫米。

“We thought these animals should have existed during this interval, but always understood they would be difficult to recognize,” said Scott Evans, a doctoral graduate at the California university. “Once we had the 3-D scans, we knew that we had made an important discovery.”

加州大学博士研究生斯科特·埃文斯说：“我们认为这些动物应该在这段时间内存在，但我们一直都知道它们很难被识别。”。“直到我们进行了三维扫描，我们就知道我们有了一个重要的发现。”

The name of the creature was a nod to the original “custodians” of the land where it was found. It’s genus, Ikaria, means “meeting place” in Australian aboriginal language.

这个生物的名字是为了向最初发现它的土地的“监护人”致敬。它的属，伊卡利亚，在澳大利亚土著语言中的意思是“聚会的地方”。

The name also comes from Warioota Creek in South Australia.

这个名字也来自南澳大利亚州的Warioota Creek。

Droser Lab/UCR/SWNS

Despite a relatively simple shape, Ikaria was actually complex in comparison to other fossils from the Edicaran Period, which spanned 94 million years from the end of the Cryogenian Period 635 million years ago to the beginning of the Cambrian Period some 541 million years ago.

尽管Ikaria的形状相对简单，但与其他埃迪卡兰时期的化石相比，Ikaria实际上是复杂的，从6.35亿年前的低温期结束到大约5.41亿年前的寒武纪时期，跨越了9400万年。

The creatures burrowed into oxygenated sand while hunting down organic matter and moved its tiny body by contracting muscles across its body like a worm, Droser said.

Droser说，这些生物在寻找有机物的同时钻入含氧的沙子中，通过像蠕虫一样收缩身体上的肌肉来移动它的小身体。

Evidence showing the creatures fed on organize matter revealed that Ikaria likely had a mouth, anus and gut, just like humans of today, Droser continued.

Droser继续说，有证据显示，这些以组织物质为食的生物很可能拥有口、肛门和肠道，就像今天的人类一样。

“This is what evolutionary biologists predicted,” she said. “It’s really exciting that what we have found lines up so neatly with their prediction.”

“这就是进化生物学家的预测，”她说。“我们所发现的与他们的预测非常吻合，这真是令人兴奋。”